Determination Of Rock Mass Mechanical Parameters And Stability Analysis On East Slope Of Yanshan Open-pit Iron Mine

Open-pit rock slope is a large scale rock engineering that is formed by excavating rock mass for mining operations.The open-pit slope sliding not only threatens the safety of the upper and lower mining operations,but also has caused huge economic losses,and even casualties.The stability of the slope is directly related to the safety production and the mining cost,and is one of the issues that need to be considered in the open pit mining.There are many factors that affect the stability of the open pit slope,but the main factors are rock composition,rock discontinuities and groundwater.Therefore,obtaining the detailed distribution of rock mass structure of slope and scientifically and reasonably determining the mechanical parameters of rock mass slope are vital for the analysis and evaluation of slope stability,as well as for slope optimization design.This paper takes the east slope of Yanshan open pit iron mine as a research object.Field geological investigation,complementary drilling for engineering geological survey,drilling photogrammetry,3D laser scanning and laboratory tests for rock mechanics are used to obtain the information of rock mass structure and rock mass mechanics parameters,then study the characterization of mechanical parameters of slope rock mass and slope stability.As a result,the corresponding prevention and control measures are also put forward.The main work is summarized as follows:Firstly,according to the actual construction of the mine,geological data obtained by existing and supplementary survey,the east slope rock mass quality is evaluated and classified,combined with the physical and mechanical parameters of the rock obtained experimentally;Secondly,with a comprehensive consideration of the influence of joints and cracks,rock structure and groundwater in rock mass,the Hoek-Brown strength criterion is used to determine the mechanical parameters of rock slope,and then considering the influence of weathering degree and the influence of bedding angle on the slope,rock mass mechanical parameters were amended and finally determined more reasonably.Finally,the limit equilibrium method(GEO slope numerical analysis software)was employed to analyze the stability of the final limit slope,which is planned according to the present mining design.It is found that there exists potential hazard for the planned limit of the east slope.Aiming at this problem,in order to ensure the safety of the exploitation of the latter and the final slope stability,two kinds of treatment plans are then proposed.The comparison of them is carried out according to slope stability and treatment cost.A reasonable plan with other auxiliary measures for guaranteeing the slope stability is recommended finally.These outcomes related to the stability of the limit slope in this paper have a significant guidance for ensuring the stability of the limit east slope of Yanshan iron mine,and guaranteeing the production safety in the deep level of the iron mine.